2008 MERCEDES-BENZ GL320 automatic transmission

195 Controls in detail
Automatic transmission
Insert the SmartKey with
KEYLESS-GO* into the starter switch.
Switch on the ignition.
Depress the brake pedal.
Shift the automatic transmission to
neutral positionN.
Release the brake pedal.
If engaged, release the parking brake
(
page 59).
Switch off the ignition and leave the
SmartKey with KEYLESS-GO* in the
starter switch.
Driving tips
Accelerator position
Your driving style influences the
transmission’s shifting behavior:
Less throttle Earlier upshifting
More throttle Later upshifting
!Observe instructions

when taking the vehicle through an
automatic conveyor type car wash
(
page 428)

when towing the vehicle (page 538)
!Coasting the vehicle, or driving for any other
reason in neutral positionN can result in
transmission damage that is not covered by the
Mercedes-Benz Limited Warranty.
Effect
êDrive
The transmission shifts
automatically. All forward gears
are available.
Warning!G
Getting out of your vehicle without shifting
into park positionP is dangerous. Also, park
positionP alone is not intended to or capa-
ble of preventing your vehicle from moving,
possibly hitting people or objects.
Always set the parking brake in addition to
shifting to positionP (
page 67).
When parked on an incline, turn the front
wheels towards the road curb.
Do not park this vehicle in areas where com-
bustible materials such as grass, hay or
leaves can come into contact with the hot
exhaust system, as these materials could be
ignited and cause a vehicle fire.
Warning!G
When leaving the vehicle, always remove the
SmartKey or SmartKey with KEYLESS-GO*
from the starter switch, take it with you, and
lock the vehicle. Do not leave children unat-
tended in the vehicle, or with access to an
unlocked vehicle. Children could shift the
automatic transmission out of park
positionP, which could result in an accident
and/or serious personal injury.
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196 Controls in detail
Automatic transmission
Kickdown
Use kickdown when you want maximum
acceleration.
Press the accelerator past the point of
resistance.
Depending on the engine speed the
transmission shifts into a lower gear.
Ease on the accelerator when you have
reached the desired speed.
The transmission shifts up again.
Stopping
When you stop briefly, e.g. at traffic lights:
Leave the transmission in gear.
Hold the vehicle with the brake.
When you stop for a longer period of time
with the engine idling and/or on a hill:
Set the parking brake.
Shift into park positionP.Maneuvering
When you maneuver in tight areas,
e.g. when pulling into a parking space:
Control the vehicle speed by gradually
releasing the brakes.
Accelerate gently.
Never abruptly step on the accelerator.
Rocking the vehicle
Rocking the vehicle by shifting between
drive positionD and reverse gearR can
help free a vehicle stuck in mud or snow.
The engine control system of this vehicle
electronically limits shifting between
drive positionD and reverse gearR to
very low speeds, i.e. approximately
5 mph (9 km/h). To shift between drive
positionD and reverse gearR, move the
gear selector lever past the resistance
point up or down.Working on the vehicle
Hill start assist system
Warning!G
When working on the vehicle, set the
parking brake and shift to park positionP.
Otherwise the vehicle could roll away.
Warning!G
The hill start assist system is not designed
to function as a parking brake and does not
prevent the vehicle from moving when
parked on an incline.
Always set the parking brake in addition to
shifting to park position
P.
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197 Controls in detail
Automatic transmission
On uphill grades with a gradient angle of
more than 5°, the hill start assist system
maintains the pressure in the brake sys-
tem for approximately 1 second after you
have released the brake pedal. Therefore,
you can start off smoothly without the
vehicle moving immediately after releasing
the brake pedal.
The hill start assist system is inactive

when starting off on a level road or
downhill grades

with the transmission in neutral
positionN

with the parking brake set

if the ESP® has switched off due to a
malfunctionTowing a trailer
If you tow a trailer, note the following
points:

Manually shift to a lower gear range
(
page 197) if the transmission hunts
between gears on inclines.
A lower gear range and reduction of
speed reduces the chance to overload
or overheat the engine.
For more information on trailer towing, see
the “Operation” section (
page 364).
Gear ranges
With the automatic transmission in drive
positionD, you can select a gear range for
the automatic transmission to operate
within.
You can limit the gear range by pressing
the left gearshift button on the steering
wheel gearshift control, and reverse the
gear range limit by pressing the right gear-
shift button on the steering wheel gearshift
control (
page 198).The selected gear range appears in the
multifunction display.
1Current gear range
Effect
ïThe transmission shifts through
sixth gear only.
îThe transmission shifts through
fifth gear only.
éThe transmission shifts through
fourth gear only.
èThe transmission shifts through
third gear only.
With this selection you can use
the braking effect of the engine.
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198 Controls in detail
Automatic transmission
Steering wheel gearshift control
With drive positionD selected, you can
limit or extend the gear range.
1Left button: limiting gear range or
downshift
2Right button: extending gear range or
upshiftEffect
çThe transmission shifts through
second gear only.
Allows the use of engine’s
braking power when driving:

on steep downgrades

in mountainous regions

under extreme operating
conditions
æThe transmission operates in
first gear only.
For maximum use of engine’s
braking effect on very steep or
lengthy downgrades.
!Allow engine to warm up under low load use.
Do not place full load on the engine until the
operating temperature has been reached.
Shift into reverse gearR or park positionP only
when the vehicle is stopped.
Avoid spinning of a drive wheel for an extended
period when driving off on slippery road
surfaces. This may cause serious damage to the
drivetrain which is not covered by the
Mercedes-Benz Limited Warranty.
iYou cannot shift with the steering wheel
gearshift buttons when the transmission is in
positionP,N orR.
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199 Controls in detail
Automatic transmission
Downshifting
Briefly press left shift button1.
The transmission will shift to the next
lower gear as permitted by the shift
program. This action simultaneously
limits the gear range of the automatic
transmission (
page 197).Upshifting
Briefly press right shift button2.
The transmission will shift to the next
higher gear as permitted by the shift
program. This action simultaneously
extends the gear range of the automat-
ic transmission (
page 197).
Canceling gear range limit
Press and hold right shift button2
until the cipher for the current gear
range disappears from the multifunc-
tion display (
page 197).
The transmission will shift from the
current gear range directly to gear
rangeD.Shifting into optimal gear range
Press and hold left shift button1.
The transmission will automatically
select the gear range suited for optimal
acceleration and deceleration. This will
involve shifting down one or more
gears.
Warning!G
On slippery road surfaces, never downshift
in order to obtain braking action. This could
result in drive wheel slip and reduced
vehicle control. Your vehicle’s ABS will not
prevent this type of loss of control.
iTo avoid overrevving the engine when down-
shifting, the transmission will not shift to a lower
gear if the engine’s max. speed would be ex-
ceeded.
iIf you press on the accelerator when the
engine has reached its rpm limit, the transmis-
sion will upshift beyond any gear range limit
selected.
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200 Controls in detail
Automatic transmission
Emergency operation (Limp-Home
Mode)
If vehicle acceleration becomes less re-
sponsive or sluggish or the transmission
no longer shifts, the transmission is most
likely operating in limp-home (emergency
operation) mode. In this mode only second
gear and reverse gear can be activated.
Stop the vehicle in a safe location.
Shift to park positionP.
Turn off the engine.
Wait at least 10 seconds before
restarting.
Restart the engine.
Shift to drive positionD (for second
gear) or reverse gearR.
Have the transmission checked at an
authorized Mercedes-Benz Light Truck
Center as soon as possible.
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201 Controls in detail
Transfer case
Transfer case
LOW RANGE mode*
The LOW RANGE mode is available on vehi-
cles with enhanced off-road package*.
In the following situations you should
switch to LOW RANGE mode:

during off-road driving (page 355)

when crossing water (page 360)

when towing up or down on steep
gradients
With the LOW RANGE selected, the
engine’s power delivery and the shifting
behavior of the automatic transmission are
adjusted. Furthermore, the ABS, ESP
® and
4-ETS functions especially adapted to
off-road travel are activated.
For information on driving safety systems
during LOW RANGE mode, see “Driving
safety systems” (
page 101).
For more information on Off-road driving,
see “Off-road driving” (
page 355).Gear Ranges
There are two possible settings.
!Operational or performance test must only
be conducted on a two-axle dynamometer. If
such tests are necessary, contact an authorized
Mercedes-Benz Light Truck Center. You could
otherwise seriously damage the brake system or
the transfer case which is not covered by the
Mercedes-Benz Limited Warranty.
!Because the ESP® operates automatically,
the engine and ignition must be shut off
(SmartKey in starter switch position0 or1 or
KEYLESS-GO* start/stop button in
position0or1) when testing the parking brake
on a brake test dynamometer and such testing
should be no longer than 10 seconds.
Active braking action through the ESP
® may
otherwise seriously damage the brake system
which is not covered by the Mercedes-Benz
Limited Warranty.
iThe vehicle is equipped with permanent
four-wheel drive. Both the front and rear axles
are powered at all times when the vehicle is
being operated.
HIGH
RANGERoad position for all normal
driving situations.
(LOW RANGE mode off)
LOW
RANGEOff-road position for traveling
on rough terrain.
(LOW RANGE mode on)
Also use the off-road position
when driving on-road on steep
gradients, especially when
towing a trailer.
LOW RANGE acts by raising
the engine’s gear ratio. The ve-
hicle travels at roughly third
the speed compared to when
in the HIGH RANGE position,
leading to an increase in the
engine’s drive power.
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202 Controls in detail
Transfer case
Switching LOW RANGE mode
The switch is located on the upper part of
the center console.
1LOW RANGE switch
2Indicator lamp
3LOW RANGE displaySwitching LOW RANGE mode on
(switching from HIGH RANGE to LOW
RANGE)
Press LOW RANGE switch1.
Indicator lamp2 flashes.
If the system senses that all conditions
are met, it will switch to LOW RANGE
mode. A chime sounds and the LOW
RANGE display3 appears in the multi-
function display.
The indicator lamp2 on the
LOW RANGE switch comes on continu-
ously, indicating that the LOW RANGE
mode has been activated.
Warning!G
Always wait until the procedure of shifting
from HIGH RANGE to LOW RANGE – and
from LOW RANGE to HIGH RANGE – has
been entirely completed. During this proce-
dure do not:

switch off the engine

shift the automatic transmission into
another gear
If you do not wait until the shifting proce-
dure has been entirely completed then it
might not be correctly performed. The trans-
fer case might be in neutral, thus interrupt-
ing the transfer of power between the
engine and the drive axle.
The vehicle is then freely movable, even if a
gear has been selected, and could uninten-
tionally be set into motion – particularly on
up – or downhill grades. This could lead to
an accident and cause injury to yourself and
others.
Please observe related messages appearing
in the multifunction display (
page 488).
!The shift procedure can only be performed
when the following conditions are met:

The engine is running (page 41).

The automatic transmission is in positionN
(
page 190).

The vehicle speed does not exceed 25 mph
(40 km/h).
iThere is no reset to HIGH after the ignition
has been switched off.
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